The present invention relates to a crop yield monitoring system and method for use during harvesting of a crop.
Load cells, such as strain gage load cells, have been used in development of yield monitors for harvesting grains, forage, potato, and sugar beet. For example, Birrell et al. in xe2x80x9cComparison of sensors and techniques for crop yield mappingxe2x80x9d, Computers and Electronics in Agriculture, 14:215-33, 1996, used a catch bin situated in a clean grain tank to provide a comparison to the grain yield indicated by commercial monitors. Wagner and Schrock in xe2x80x9cYield Determination Using Pivoted Auger Flow Sensorxe2x80x9d, Transactions of the ASAE, 32(2): 409-13, 1989, replaced an existing clean grain elevator with a triangular auger system to provide a horizontal section of flowing grain. This horizontal section was supported on one end by a pin connection and on the other end by a load cell. The load cell provided instantaneous weight measurements which were used to derive material flow rate.
Rawlins et al. in xe2x80x9cYield Mapping of Potatoxe2x80x9d, In-Site-specific Management for Agricultural Systems, 59-68, Madison, Wis., ASA-CSSA-SSSA 1995, and Campbell et al. in xe2x80x9cMonitoring Methods for Potato Yield Mappingxe2x80x9d, ASAE paper #94-1584, St. Joseph, Mich., 1994, developed a system in which a section of a conveyor on a potato harvester was supported by load cells integrated into idler wheel mounts. In this system, instantaneous conveyor section weights and conveyor speed measurements were used to obtain mass flow rate of potato which was referenced to position data simultaneously collected with a global position system receiver. This yield monitor, now commercially available as the HarvestMaster monitor from HarvestMaster, Inc. Logan, Utah, is used for sugar beet and potato yield monitoring.
Yield monitoring of forage was attempted and described by Wild et al. in xe2x80x9cAutomatic Data Acquistion on Round Balersxe2x80x9d, ASAE Paper #94-1582, St. Joseph, Mich. 1994. A round baler was equipped with load cells that monitored the weight of the entire machine as the forage was collected. Preliminary results showed that individual bale weights could be accurately determined under static conditions, but excessive noise severely limited real time yield measurements. The tractor and baler also were instrumented with accelerometers to monitor vibration. Acceleration thresholds were used to screen data for real-time measurement, but the signal noise remained a severe limitation to forage yield monitoring.
Machine vibration is an unfortunate but real characteristic of all harvesting equipment. Rotating shafts and other undulating parts drive the cutting, threshing and transport operations within both self-propelled and tractor-driven combines. Any sensor installed within a combine must be able to endure vibration, and the data acquisition system or subsequent analysis must likewise be able to produce usable data from the sensor output. Strain-gage based sensors are particularly sensitive to vibration.
Spectral analysis provides a useful method for evaluating machine vibrations. These techniques were used by Wagner and Schock in aforementioned xe2x80x9cYield Determination Using Pivoted Auger Flow Sensorxe2x80x9d, Transactions of the ASAE, by Pringle et al. in xe2x80x9cYield Variation in Grain Cropsxe2x80x9d, ASAE paper #93-1505, St. Joseph, Mich. 1993, and by Elliot et al. in xe2x80x9cEvaluation of Dynamic Noise Sources in a Real-Time Soil Sensorxe2x80x9d, ASAE paper 394-1579, St. Joseph, Mich., 1994, to determine the needed sampling rate and the characteristics of the filters to be used.
Analog filtering techniques to remove vibration and other electrical noise in yield monitoring systems are presented by DeBaerdemaeker et al. in xe2x80x9cMonitoring the Grain Flow on Combinesxe2x80x9d, Agri-Mation 1. ASAE, 329-338, 1985, by Vansichen et al. in xe2x80x9cA Measurement Technique for Yield Mapping of Corn Silagexe2x80x9d, Journal of Agricultural Engineering Research, 55:1-10, 1993, by Pringle et al, in aforementioned xe2x80x9cYield Variation in Grain Cropsxe2x80x9d, ASAE paper #93-1505, by Vansichen et al. in xe2x80x9cContinuous Wheat Yield Measurement on a Combinexe2x80x9d, Automated Agriculture for the 21st Century, ASAE, 346-355 1991, and by Schrock et al. in xe2x80x9cSensing Grain Yield with a Triangular Elevatorxe2x80x9d, Site-Specific Management for Agriculture Systems, ASA-CSSA-SSSA, 1995.
Digital filtering techniques were used in yield monitoring research by Wagner and Schock in aforementioned xe2x80x9cYield Determination Using Pivoted Auger Flow Sensorxe2x80x9d, Transactions of the ASAE, by Vansichen et al. in aforementioned xe2x80x9cContinuous Wheat Yield Measurement on a Combinexe2x80x9d, Automated Agriculture for the 21st Century, ASAE, by Birrell et al. in aforementioned xe2x80x9cComparison of sensors and techniques for crop yield mappingxe2x80x9d, Computers and Electronics in Agriculture, by Pringle in aforementioned xe2x80x9cYield Variation in Grain Cropsxe2x80x9d, ASAE paper #93-1505, by Vansichen et al. in aforementioned in xe2x80x9cA Measurement Technique for Yield Mapping of Corn Silagexe2x80x9d, Journal of Agricultural Engineering Research, and by Murphy in xe2x80x9cYield Mapping-A Guide to Improved Techniques and Strategiesxe2x80x9d, Site-Specific Management for Agricultural Systems, 33-47, ASA-CSSA-SSSA, 1995.
Yield monitoring studies have recognized a problem of delay, or lag, between the moment that the crop enters the combine and the moment that it is sensed. If no compensation technique is used to correct or minimize this problem, the spatial representation of the yield data will be misleading. Lamb et al. report in xe2x80x9cPerils of Yield Monitoring on the Goxe2x80x9d in Proceedings of the Second International Conference on Site Specific Management for Agricultural Systems, Madison Wis.: ASA-CSSA-SSSA, 1995, that a time lag of 15 seconds with the average harvest speed of 5.1 km/h (3.2 mi/hr) will displace true yield data by as much as 20.1 meters (66 feet). Searcy et al. in xe2x80x9cMapping of Spatially variable Yield During Grain Combiningxe2x80x9d in Transactions of the ASAE, 32 (3):826-9, 1989, proposed mathematical models to reconstruct the actual yield data from the measured yield data. They used a first order transfer function model and considered the combine as a lumped parameter system. Also see Vansichen and De Baerdemaeker article entitled xe2x80x9cA Measurement Technique for Yield Mapping of Corn Silagexe2x80x9d in Journal of Agricultural Engineering Research, 55:1-0, 1991. Birrell and Borgelt in xe2x80x9cCrop Yield Mapping: Comparison of Yield Monitors and Mapping Techniquesxe2x80x9d in Site-Specific Management for Agricultural Systems, 15-31, Madison, Wis. ASA-CSSA-SSSA, 1995, experimented with both simple delay and the transfer function model. Their results showed that the transfer function was a better model for describing the xe2x80x9cstepxe2x80x9d input of crop at the beginning of a row; however, the noise amplification involved in inverting the transfer function data from the frequency domain to the time domain reduced the usefulness of this method. Depending on the desired yield resolution (harvested crop per unit area), the added complexity of the transfer function may be counterproductive to the yield monitor design.
Yield monitoring systems have been developed for grain harvesting in order to promote precision farming operations. However, a yield monitoring system for harvesting peanuts is not available today in part due to the functionally different nature of peanut harvesting and peanut combines.
In particular, peanut plants are mechanically dug, the fruit (pods) and vines are shaken free of soil, and the whole plant inverted before being laid back on the soil surface. The peanut plants remain on the surface to cure (dry) to a moisture content suitable for harvest (e.g. less than 12-18%) and pod removal. With the dried peanut plants arranged in windrows, a peanut combine uses a pickup reel to harvest the windrows. The pickup reel feeds the cured plants onto a throat elevator where they are drawn through a series of rotating cylinders and sieves to separate the pods from the vines. The pods fall through the sieve into a collecting hopper where either a mechanical lateral floor auger or a fan moves them across the bottom of the combine and into an air duct. On all current peanut combines, the peanut pods are blown from the base of the combine through an air duct into a collecting basket on the top of the combine.
Because peanut pods are blown into the collecting basket atop the combine, existing grain yield monitoring systems are not directly applicable. For example, most of the current grain yield monitoring systems rely on a pulsed or continuous flow of grain from a lifting auger. Grain transported by an auger maintains a consistent speed relative to the auger and a force-based sensor can be used. The ability to calibrate grain impact on a sensor/plate to the auger speed has been shown to be a commercially acceptable means to monitor grain yield.
There thus is a need for a yield monitoring system and method for peanut combines and other similar harvesting machines where the harvested crop is transported into a collection basket or container.
It is an object of the present invention to satisfy this need.
The present invention provides a crop yield monitoring system and method based on measuring mass changes in a crop collection basket of a harvesting machine, such as a peanut combine, as a crop field is being harvested and including load cells supporting the collection basket and a data acquisition system for acquiring incremental load cell output and preferably using digital noise filtering to remove signal noise resulting from harmonic vibration of a one or more components of the harvesting machine, such as for example only, a straw walker mechanism of a peanut combine.
In an illustrative embodiment of the invention offered to illustrate and not limit the invention, a peanut combine towed by a tractor during harvesting includes a collection basket disposed on a pivotable support frame mounted on the top of the combine. The basket support frame is supported on four load cells mounted in rigid channels on the top of the combine. A respective load cell is located beneath and adjacent to each lower bottom corner of the collection basket between the support frame and the channels. The load cells produce analog data output or signals representative of weight of the collection basket at any given instance as the crop is harvested. The load cell output is provided to a data acquisition system (DAS) that includes a CPU (computer processor unit) via a signal summing device and an analog anti-alias filter. The DAS includes an analog-to-digital converter to convert the analog load cell output to digital output for further processing and digital filtering to remove signal noise attributable primarily to the straw walker of the combine. The CPU is interfaced with a global positioning system receiver that provides time, latitude and longitude information of the combine to the CPU and also with a sensor that inputs tractor/combine information to the CPU from which speed of the combine can be determined. An interface device is provided on the tractor and interfaces with the CPU for providing signals representative of the number of rows harvested to the CPU as input by the tractor operator. The CPU determines the instantaneous crop yield, crop yield rate and area harvested as a crop field is being harvested for display to the tractor operator.
The invention is advantageous to provide a crop yield monitoring system and method which can be used during harvesting of a crop, such as peanuts, pecans, Vidalia onions, and others, which are transported into a collection basket in order that crop yield can be determined based on measuring mass changes of the collection basket. The invention provides crop yield mapping data for evaluating crop yield at locations in a site-specific farming area. These advantages are obtained using load cells and other system components mounted in a manner for ready retrofitting on existing combines and also as original equipment on new combines.
The above and other objects and advantages of the present invention will become more readily apparent from the following detailed description taken with the following drawings.